The present invention relates to a method for coating a molded part, in particular a molded part produced by injection molding.
Molded parts, in particular molded parts produced by injection molding, are often provided with a coating, for example in order to protect them from external effects or also owing to visual requirements. A possibility for providing the molded part with a coating consists in firstly producing the molded part without a coating, for example in an injection molding machine, and in subsequently coating the molded part at a separate location. For this, the molded part can be conveyed for example by means of a conveyor belt from the injection molding machine into a lacquering chamber, where it then receives a coating in the form of a lacquer.
However, the problem exists there that during the conveying between injection molding machine and lacquering chamber, dust and other particles can become deposited on the molded part. These particles lead to the subsequently applied coating not adhering on the molded part over the entire surface, which inter glia can lead to the coating being limited in its durability.
For this and other reasons, it is desirable to already provide molded parts with a coating in the injection molding machine itself.
From DE 10 2007 021 679 A1 a method for expansion flooding is known. In this method, firstly a molded part of plastic is produced in an injection molding machine. Subsequently, the molded part is removed by means of a cavity core a distance away from the one molding-tool half, whereby a cavity is produced between the molded part and this molding-tool half, into which cavity then a second component, for example a coating, can be filled.
Whilst the known method for expansion flooding enables a coating of the molded part in the injection molding machine, it would be desirable to simplify the structure of the device provided for the method, because in the known method a separate stamping core is necessary. In addition, in the case of very low-viscosity coatings and lacquers, which in part have a lower viscosity than water, it can occur that a seal can not be ensured between the molded part and an adjacent molding-tool half.
An insufficient seal has, inter alia, a great influence on the quality of the finished product and also on the reject rate of defective products. As the defective products can not be readily recycled, due to the fixed connection between molded part and coating, there is a need for improvement in this respect.